The subject invention relates to an intravascular (xe2x80x9cIVxe2x80x9d) medical device. More specifically, this invention relates to an IV catheter that is adapted to be affixed to the patient""s skin. Even more specifically this invention relates to an IV catheter having wings that are each formed with a stiffening member therein. In addition, this invention relates to a catheter wing and stiffening member configuration and method for forming the catheter wing and stiffening member that maintains the ornamental and functional features of the wing and stiffening member. The invention results in a catheter wing that facilitates the introduction of the catheter into a patient""s vasculature yet maximizes patient comfort when the wing is affixed to the patient""s skin.
In order properly to place an IV catheter into a patient, the catheter is typically mounted over an introducer needle having a sharp distal tip. At least the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter and thus facilitates insertion of the catheter into the blood vessel. The distal tip of the needle preferably extends beyond the distal tip of the catheter with the bevel of the needle facing up away from the patient""s skin.
The catheter and introducer needle assembly is inserted at a shallow angle through the patient""s skin into a blood vessel. Some catheters include wings, which may be used to facilitate this venipuncture and to facilitate securing the catheter to the patient as discussed below. The wings extend from either side of the catheter or catheter hub and aid the clinician to precisely manipulate and control the position of the catheter during venipuncture. In some cases the wings may be folded together like butterfly wings. In order to verify proper placement of the catheter in the blood vessel, the clinician confirms that there is flashback of blood in a flashback chamber. The flashback chamber is typically formed as part of the needle hub. Once proper placement of the catheter into the blood vessel is confirmed, the clinician applies pressure to the blood vessel by pressing down on the patient""s skin over the blood vessel distal of the needle and the catheter. This finger pressure occludes or at least minimizes further blood flow through the needle and the catheter. The clinician then withdraws the needle, leaving the catheter in place for use in accordance with standard medical technique.
Peripheral IV catheters are short, and are typically on the order of between about xc2xe of an inch and about 3 inches long. Because of the shortness of the catheter, it is typically taped or sutured to the patient""s skin. Taping or suturing the catheter to the patient""s skin minimizes the possibility that the catheter will become dislodged from the patient""s vein if the patient moves or a clinician manipulates the catheter to connect or disconnect an IV line or other medical device. To facilitate this taping or suturing, some catheters include wings extending about 180 degrees apart from either side of the catheter hub. In some devices, the ends of the wings include suture holes that allow the clinician to sew the catheter directly to the patient""s skin.
In order to maximize patient comfort, these wings are typically formed from a soft and flexible material such as silicone. This type of material is comfortable to the touch and has no hard portions that could dig into the patient""s skin causing abrasions or pressure points. However, materials having the desired softness for maximizing patient comfort may not have sufficient rigidity to allow the clinician to precisely manipulate and control the position of the catheter during venipuncture. Such softness and flexibility could allow the wings to flex or fold so that when the clinician grasps the catheter by the wings, the catheter may not be properly aligned with the longitudinal and radial axis of the wings. This makes it difficult for a clinician to use the wings to control the location of the catheter with respect to the wing and the venipuncture site. To date, an appropriate balance between soft, flexible wings that maximize patient comfort when the catheter is affixed to the patient""s skin and hard, stiff wings that maximize the ability of the clinician to precisely control the catheter during venipuncture has not been found in available devices.
It is therefore an object of this invention to provide a catheter that maximizes patient comfort when the catheter is affixed to the patient""s skin and that also maximizes the ability of the clinician to precisely control the catheter during venipuncture.
It is another object of this invention to provide a catheter wing configuration that balances the functional and ornamental characteristics of wings formed from soft, flexible material and wings formed from hard, rigid material.
It is yet another object of this invention to provide a method for forming a catheter wing configuration that achieves the objects of this invention.
This invention is particularly useful when applied to a catheter, especially a catheter having an integrated extension tube extending from the catheter adapter (an xe2x80x9cintegrated catheterxe2x80x9d), although it is to be understood that this invention is applicable to other medical devices that require wings to facilitate both affixing the device to the patient""s skin or precisely manipulating the medical device.
The catheter is coaxially disposed over the introducer needle with the distal portion of the catheter tightly engaging the outer surface of the introducer needle. This prevents peelback of the catheter and facilitates insertion of the catheter into the patient""s blood vessel. Prior to use, the catheter is located about the introducer needle so that the sharp distal tip of the introducer needle is distal of the distal end of the catheter. The proximal end of the catheter is connected to a catheter adapter. A pair of wings extends about 180 degrees apart from either side of the catheter adapter. The ends of each wing may define a suture hole that allows a clinician to sew the wing, and thus the catheter, directly to the skin of the patient.
The introducer needle has a sharp distal tip and a proximal end connected to the distal end of a needle hub and preferably includes at least one notch, i.e. a hole or opening in the sidewall, therein in communication with the needle lumen. The notch is formed in the introducer needle such that blood can flow into the open distal end of the introducer needle, through the lumen in the introducer needle and through the notch outside the introducer needle into the catheter lumen. Thereafter, the blood can flow through the annular space between the outside of the introducer needle and the inside of the catheter and catheter adapter and then through the side arm and extension tube that extends from the catheter adapter. Preferably, the catheter, catheter adapter and the extension tube are transparent or at least translucent. In this way, the clinician can immediately and easily visualize flashback of blood through these parts of the catheter assembly when the introducer needle has been inserted into a patient""s blood vessel.
If desired, a needle shield movably disposed about the introducer needle and located distally of the needle hub is defined by a housing having an internal cavity through which the introducer needle extends. A lock associated with the needle shield prevents unwanted distal movement of the introducer needle once the introducer needle has been proximally withdrawn into the needle shield. Also associated with the needle shield is a means for preventing unwanted proximal movement of the introducer needle once the sharp distal tip of the introducer needle has been proximally withdrawn into the needle shield.
The catheter wing includes a stiffening member disposed therein. Preferably the wing is formed from a thermoplastic elastomer. The stiffening member may be formed from the same material used to form the catheter adapter and is preferably a polycarbonate material or polyethylene phthalate glycol (PETG). The soft, flexible material of the wing is comfortable to the touch and covers any hard edges or other surfaces to prevent skin abrasion or pressure points on the patient""s skin when the wing is taped to or sutured onto the patient""s skin. The hard, rigid material of the stiffening member provides rigidity to the wing to allow the clinician to precisely control the position and movement of the catheter.
Suture holes may be formed at the ends of each wing. These suture holes provide a dual function. As is standard with all suture holes, the suture holes of this invention provide a mechanism that allows the clinician to sew the wings, and thus the catheter, directly to the patient""s skin, which fixes the catheter in place. In addition, the suture holes provide a mechanism to hold the stiffening members in place when the wings are formed. The wings are formed by injection molding the wing material over the stiffening members. Without some fixation device to hold the stiffening members in place, the high pressure used during the injection molding process will cause the stiffening members to become dislodged with the result that they will not be located in the optimum position within the wing. With the suture holes of this invention, pins can be used during the molding process to precisely locate the stiffening members with respect to the wing to be overmolded thereon. This prevents the stiffening members from becoming dislodged from their location even under the high pressure of the injection molding process. Alternatively, the ends of the stiffening members could be formed with upwardly and downwardly extending integral pins. These pins in turn would sit in appropriate holes formed in the mold to precisely locate the stiffening members with respect to the wing to be overmolded thereon.